Recent developments in wireless telecommunications have ushered in a new era of mobility. The advent of cellular and personal communications services has enabled people to maintain communication from virtually any location. Further, advanced technology has facilitated not only wireless voice communication but also wireless data communication, such as the ability to communicate over computer networks and to send and receive data and other content.
Wireless communications systems have existed for many years. In general, a wireless communications system uses mobile or fixed radios that communicate with a fixed radio tower that is in turn interconnected to a larger telecommunications network. Such systems can take a variety of forms. For example, traditional cellular communications systems provide radio coverage to a wide area, such as a city, through use of many radio towers. Typically, subscribers to wireless service are equipped with one or more wireless terminals or “client devices,” which may take any of a variety of forms. By way of example, a wireless client device may be a telephone, a pager, a computer, a personal digital assistant (“PDA”) or any combination of these or other devices. A wireless client device may be configured to receive and/or convey information such as voice and data (e.g., fax, e-mail and other text messages) and/or other media (e.g., audio, video and graphics). Further, the client device may include input and output facilities such as a touch-pad, a keyboard, a camera, a display, a microphone and/or a speaker. Some client devices are equipped with web browsing software to allow subscribers to communicate with web servers over an Internet Protocol (IP) network (i.e., the Internet).
Wireless networks and mobile wireless devices may use a number of channels to transmit and receive information, and a properly equipped wireless device can initiate communications by sending an initiation request message over one of these channels. Applying industry standards, the initiation request message may include a code that characterizes the requested communication as packet-data communication, as compared with traditional voice communication.
With the rapid growth in the area of wireless communications, a variety of different access technologies has emerged. For example, Code Division Multiple Access (CDMA) is a packet-based wireless-access technology that may be used in certain cellular phone systems. As another example, Wi-Fi is an access technology based on a series of specifications from the Institute of Electrical and Electronics Engineers (IEEE) called 802.11. Wi-Fi uses radio frequency and enables a wireless-enabled computer or PDA to connect to the Internet via a wireless access point. Yet another access technology being utilized today is commonly referred to as WiMax (Worldwide Interoperability for Microwave Access). WiMax, also known as the IEEE 802.16 group of standards, defines a packet-based wireless technology that provides high-throughput broadband connections over long distances.
With different access technologies in use today, a variety of problems currently exist in the art. For example, there exist problems associated with allowing devices utilizing different technologies to communicate with one another and allowing a mobile device to move between access technologies. Indeed, separate systems are currently required to support IP connectivity for each individual access technology. This is because the standards bodies that created the standards for the different technologies individually created different requirements for IP connectivity over the various technologies. The result of this approach is an IP handoff for devices moving between technologies. However, as service providers strive to deploy real time services across wireless infrastructures, it is becoming increasing important to minimize such IP handoffs. This is because the handoffs require additional signaling and registration elements, and they introduce extra routing hops and latency. Accordingly, there is a need for improved mechanisms for efficiently establishing and maintaining connectivity with client devices over a plurality of access technologies.